Genesis 15:12-16

As the sun was going down, a deep sleep fell on Abram. And behold, dreadful and great darkness fell upon him. Then the LORD said to Abram, “Know for certain that your offspring will be sojourners in a land that is not theirs and will be servants there, and they will be afflicted for four hundred years. But I will bring judgment on the nation that they serve, and afterward they shall come out with great possessions. As for you, you shall go to your fathers in peace; you shall be buried in a good old age. And they shall come back here in the fourth generation, for the iniquity of the Amorites is not yet complete.”